Question

A rectangular coil of 20 turns and area of cross-section 25 s cm has a resistance of 100 $\Omega$. If a magnetic field which is perpendicular to the plane of coil changes at a rate of 1000 tesla per second, the current in the coil is

• A. 1A
• B. 50 A
• C. 0.5 A
• D. 5 A

Answer 1

Answer: (C)

0.5 A

Answer 2

The formula can be expressed as i = Ɛ/R

Now, Ɛ = NA (dB/dt)

According to the problem– N=20, A=25cm2= 25x10-4 cm2, R=100Ω, dB/dt= 1000Ts-1

Therefore, i =[NA(dB/dt)] / R = [20x25x10-4x1000] / 100

∴ i = 2x25x0.01 = 0.5A

So, the resultant current is 0.5 amp.

A wire coil wound around an electrical conductor is referred to as a current coil. The wire in this case is typically insulated copper wire. A soft iron core serves as the conductor. Electromagnetism is shown via the current coil conductor experiment.

A few applications of such coil are–

• Unlike a conventional permanent magnet, an electromagnet may be switched on and off as needed.
• Can crushers be made using current coils? It relies on the electromagnetic field's effect to function. When a can is placed within a coil, a greater electromagnetic field is produced. The can is bent and deformed into a flat disc by energizing the coil.
• Typically, current coils are employed as electromagnets. Different varieties of electromagnets exist, including degaussing coils, Maxwell coils, solenoid coils, voice coils, etc.
• Magnetic cranes are constructed using current coils. Huge metal debris can be dumped on the other side of an electromagnet that has been de-energized after being attracted to it by electricity in landfills.